Method for the preparation of a fuel composition for use in gasoline engines and blending component

ABSTRACT

A method for the preparation of a fuel composition for use in gasoline engines and a blending component is provided, in which the fractions from cracking apparatus is used. In the method, light cycle oil obtained from fluid catalytic apparatus is subjected to fractionation and used as a blending component. The blending component obtained by fractionation has a distillation characteristic of from 160 to 230° C., a content of aromatic hydrocarbons with 9 or more carbon atoms of amount not less than 80% by volume and an indane content of amount not less than 20% by volume.

This invention relates to a method for preparation of fuel compositionsfor use in gasoline engines as used by the gasoline engines installed inautomobiles and the like, and to a blending component for fuels used inautomotive engines.

Fluid catalytic cracking has been widely adopted as a process to obtainas far as possible the so-called white oils (blending components forgasoline fuels, light oil fuels and so on) that are much in demand bysociety. With vacuum gas oils and residual oils as the raw material,this fluid catalytic cracking apparatus can produce mainly gasoline andmiddle distillates of high octane number, and light olefins. Of theproducts produced by this method, the fractions with a distillationcharacteristic of approximately 30 to 200° C. are known as crackedgasolines, or as FCC gasolines after the fluid catalytic cracking (FCC)process, and are used as major blending components of fuel compositionsfor use in gasoline engines. Fractions of boiling points higher thancracked gasolines are further fractionated into light fractions(distillation characteristic up to 380° C.) in order to obtain middlefractions, and recovered as light cycle oil (hereinafter referred to asLCO). This LCO is utilised mainly as a blending component for heavy oil“A”, but because it has a low cetane number the situation is that thereare constraints on its use as a blending component for heavy oil “A” indiesel engines.

There have therefore been attempts to make effective use of this LCO asa fuel for automotive engines. For example, Japanese Laid-open PatentSpecification No. 2008-127542 discloses a method for the preparation ofa blending component for fuels used in gasoline engines in which LCO iscontacted with a specified crystalline aluminosilicate zeolite catalystunder certain reaction conditions. However, the LCO is furtherhydrocracked in the disclosed procedure, so that there is a problem inthat further plant investment and utility costs are required, making itmore expensive. In addition, because the characteristics which arenecessary during compounding of the gasoline, in particular thedistillation characteristics which impact on driving performance of theautomobiles, have not been disclosed, it is unclear what the impact ondriving performance is.

Therefore, the present invention has as its objective to offer a fuelcomposition preparation method in which the fractions from crackingapparatus can be used effectively for fuel compositions for use ingasoline engines, and a blending component for fuels used in automotiveengines which uses this method of preparation.

In the method for preparation of fuel compositions for use in gasolineengines relating to this invention, light cycle oil (LCO) produced byfluid catalytic cracking apparatus is subjected to fractionation andincorporated as a blending component.

In this invention, light cycle oil (LCO) has the meaning of a fraction,being produced in a catalytic cracking apparatus and being a kerosenefraction known as a middle distillate, with a distillationcharacteristic of up to 380° C.

It is preferable if the distillation characteristic of the blendingcomponent obtained by means of the aforementioned fractionation is from160 to 230° C., the content of aromatic hydrocarbons with 9 or morecarbon atoms is of amount not less than 80% by volume and the indanecontent is of amount not less than 20% by volume. What is meant by anindane is such as 2,3-dihydroindene (indane) optionally substituted byat least one functional group which is a hydrocarbon such as an alkylgroup, preferably a C₁- to C₄-alkyl group.

In the present invention, there is no particular restriction on thenumber of carbon atoms in the alkyl group bonded to the indane or on thenumber of groups, but it is preferable if the number of carbon atoms inthe total indane molecule is not more than 12. If the number of carbonatoms is more than 12, the heavy fractions in the blending component ofthe gasoline engine fuel obtained will increase and the distillation endpoint will increase, which is not desirable. As specific examples ofindanes, mention may be made of 2,3-dihydroindene (indane),5-methylindane, 4-methylindane, 1,2-dimethylindane, 1,3-dimethylindane,1,4-dimethylindane, 1,5-dimethylindane, 1,6-dimethylindane,1,7-dimethylindane, 1,4,5-trimethylindane, 1,4,6-trimethylindane,2,4,5-trimethylindane, and 2,4,6-trimethylindane.

Also, the blending component for automotive engine fuels of the presentinvention is one that can be used in the method for preparation of fuelcompositions for use in gasoline engines of the present invention. Inother words, it satisfies the condition that it is obtained byfractionation of light cycle oil obtained from fluid catalytic crackingapparatus, and the distillation characteristic is in the range of from160 to 230° C., a content of aromatic hydrocarbons with 9 or more carbonatoms is of amount not less than 80% by volume and an indane content ofamount not less than 20% by volume.

By means of the present method for preparation of fuel compositions foruse in gasoline engines, it is possible to satisfy the characteristicsrequired of a fuel composition for use in gasoline engines, because LCO,which has not been used in gasoline hitherto, is fractionated andblended as a component which has a high (at least 93) research octanenumber (hereinafter RON), and it is thus possible to make more effectiveuse of fractions from cracking apparatus. By incorporating the blendingcomponent (hereinafter referred to as LLCO) obtained by fractionation ofthe LCO, it is possible to effect an improvement in drivability andacceleration properties of fuel compositions for use in gasolineengines. In addition there is the advantage that it is possible toimprove fuel consumption by increasing the per-volume calorific heat.

The fractionation conditions for LCO should be set as appropriate bytaking into account the balance of LCO characteristics and otherblending components. In the case where LLCO is obtained by fractionationof ordinary LCO, the content of aromatic hydrocarbons with not less than9 carbon atoms is in the amount of approximately 70 to 90% by volume,and the indane content is about 15 to 25% by volume. From the standpointof high-speed acceleration properties and fuel consumption, it ispreferable if the LLCO cut temperature is made higher, but if thedistillation end point exceeds 230° C., there will be undesirableproblems in that the fuel composition for use in gasoline engines willbe made excessively heavy, or the proportion that can be blended in willbe restricted.

The proportion of LLCO in the blend can be suitably set in the range offrom 4 to 10% by volume so that the characteristics of thegasoline-engine fuel composition will be within the desired ranges, butgiven that its distillation characteristics are heavier than forgasoline-engine fuel compositions, in order to satisfy the JIS standardfor automobile gasolines (JIS K 2202), it is necessary in particular tolimit the proportion in the blend so that the distillation temperatureat 90 vol % distilled (T90) is not more than 180° C. and further thatthe distillation end point (EP) is not more than 220° C. It is alsonecessary to minimise impact on practical performance as an automotivegasoline engine fuel. Accordingly, the preferred blend proportion is inthe range of from 4 to 7% by volume.

The blending component for automotive engine fuels relating to thisinvention is one that has a distillation characteristic of in the rangeof from 160 to 230° C., a content of aromatic hydrocarbons with 9 ormore carbon atoms of amount not less than 80% by volume, and an indanecontent of amount not less than 20% by volume, and corresponds to thealready mentioned LLCO. Also as already mentioned, it can be obtained byfurther fractionation of light cycle oil corresponding to the kerosenefraction known as middle distillates. This LLCO has a high RON of atleast 93, and so satisfies the characteristics required of fuelcompositions for the gasoline engines being manufactured. It makes itpossible to recover more fractions from cracking apparatus and toproduce the blending component for gasoline-engine fuel compositions.Because it also contains many indanes, it can also improve theacceleration properties at high speeds, and because the per-volumecalorific value is at least 11% higher than commercial gasoline fuels,it is possible to improve fuel consumption. Also, whilst containing manyheavy aromatic hydrocarbons, it contains hardly any existent gum incomparison with fractions obtained from reformates of similardistillation characteristics, so that it has the advantage of having noeffect on the amounts of other additives such as detergents.

In method of the present invention, the LLCO should be blended as acomponent together with ordinary gasoline blending components. Asexamples of ordinary gasoline blending components, mention may be madeof the following.

“Desulphurised Light Naphtha”

This is a blending component obtained by desulphurisation of a naphthaobtained from a crude oil atmospheric distillation apparatus, and thenby separation into low boiling point fractions by means of distillation.

“Isomerised Gasoline”

This is a blending component obtained by isomerisation of theaforementioned desulphurised light naphtha.

“Catalytic Reformate”

This is a blending component obtained by desulphurisation of a naphthaobtained from a crude oil atmospheric distillation apparatus andreforming of the remaining heavy fraction separated off by distillationof the aforementioned desulphurised light naphtha, using for example acatalytic reforming method such as Platforming.

“Debenzenated Light Catalytic Reformate”

This is a blending component obtained by separating the aforementionedcatalytic reformate into fractions with a boiling point lower thanbenzene by means of distillation.

“Raffinate Fraction”

This is a blending component obtained by further distillation of a heavycatalytic reformate obtained by fractionation in the form of fractionswith a high boiling point by means of distillation from theaforementioned catalytic reformate, and by taking the fractions obtainedby separation of fractions which contain benzene therefrom as theremainder from which the benzene is extracted and removed by using, forexample, a solvent such as Sulfolane.

“Catalytic Reformates with 7 Carbon, 8 Carbon, or 9 or More CarbonAtoms”

These are blending components obtained by further distillation of aheavy catalytic reformate obtained by fractionation in the form offractions with a boiling point higher than benzene by means ofdistillation from the aforementioned catalytic reformate, andfractionation into fractions that contain mainly aromatics with 7carbons, aromatics with 8 carbons and aromatics with 9 or more carbons.

“Catalytically Cracked Gasoline”

This is a blending component obtained by catalytically cracking heavyoil.

“Thermally Cracked Gasoline”

This is a blending component obtained by thermally cracking heavy oil.

“Light Catalytically Cracked Gasoline and Desulphurised HeavyCatalytically Cracked Gasoline”

These are blending components obtained by distillation of theaforementioned catalytically cracked gasoline obtained by catalyticcracking of heavy oil to separate it into fractions with a low boilingpoint and fractions with a high boiling point. In the case of the lightfractions, the blending component is the result of treating thefoul-smelling light sulphur compounds such as mercaptan by sweeteningmethods such as the Merox method. In the case of the heavy fractions,the blending component is the result of removing the sulphur componentwhile ensuring that the reduction in the octane number through olefinhydrogenation is minimised, by using a selective desulphurisation methodsuch as Prime-G+.

“Light Thermally Cracked Gasoline and Heavy Thermally Cracked Gasoline”

These are blending components obtained by separation into fractions witha low boiling point and fractions with a high boiling point bydistilling the aforementioned thermally cracked gasoline obtained bythermally cracking heavy oil.

“Alkylate”

This is a blending component obtained by addition of lower olefins(alkylation) obtained as a by-product from catalytic cracking apparatusto hydrocarbons such as isobutane.

“Butane/Butylene Fraction”

This is a blending component obtained by refining petroleum gasesobtained as a by-product from apparatus such as atmospheric distillationapparatus, naphtha desulphurisation apparatus, catalytic reformingapparatus or catalytic cracking apparatus.

“Oxygenates Such as Alcohols or Ethers”

Mention may be made specifically of, for example, methanol, ethanol andpropanol for alcohols. As examples of ethers mention may be made of MTBE(methyl tertiary butyl ether) and ETBE (ethyl tertiary butyl ether).

The types of gasoline blending components used are selected asappropriate to conditions such as the make-up of the apparatus at therefinery. There is no need for all the types of blending component to bemixed in. Consequently, the proportion of any types not used is 0% byvolume. Also, when the sulphur content of the LLCO obtained byfractionation of LCO is high, it is possible to carry out, as needed, adesulphurisation treatment such as hydrorefining or adsorptiondesulphurisation.

EXAMPLES

LCO obtained from a catalytic cracking apparatus was further separatedin a distillation apparatus into light fractions and heavy fractions. Alight-fraction LLCO with a distillation characteristic of initialboiling point to 230° C. was obtained. A fuel composition for use ingasoline engines was compounded by blending the LLCO in a commercialpremium gasoline (PG) and a commercial regular gasoline (RG). Table 1shows the characteristics of the LLCO, and Tables 2 and 3 show thecharacteristics of fuel compositions for use in gasoline engines whichincluded the LLCO (Embodiments 1 to 4 and Comparative Example 1). Tables2 and 3 also show, in the form of Comparative Examples 2 and 3, thecharacteristics of the PG and the RG used in the compounding.

The methods of measurement of the properties shown in Tables 1 to 3 wereas follows.

Density

Measured in accordance with JIS K 2249 “Crude Oil and PetroleumProducts—Determination of Density and Density/Mass/Volume ConversionTables”.

Distillation Characteristic

Measured in accordance with JIS K 2254 “Petroleum Products—DistillationTest Methods”.

Octane Number

Measured in accordance with the method for determination of researchoctane number of JIS K 2280 “Petroleum Products—Fuel Oils—Determinationof Octane Number and Cetane Number, and Method for Calculation of CetaneIndex”.

Composition/Aromatics

Measured in accordance with JIS K-2536-2 “Petroleum Products—Method forDetermination of Constituents. Part 2: Determination of All Componentsby Gas Chromatographs”.

Total Calorific Value

Measured in accordance with JIS K 2279 “Crude Oil and PetroleumProducts—Method for Determination of Calorific Value and Method forEstimation by Calculation”.

Fuel Consumption

Measured by the TRIAS test method on a chassis dynamo. The test wasperformed in JCO8 mode (hot start) after sufficient running in warm air.The fuel consumption was calculated from the amount of exhaust gasesproduced during the test by using a carbon balance equation, and therate of improvement in fuel consumption was expressed as a relativevalue, taking the commercial PG and commercial RG fuels as a basis.

Acceleration Properties

Three time spans were set up at intervals of 10 km/h, from 70 km/h to100 km/h, and the times to reach the respective vehicle speeds weremeasured on a chassis dynamo. The improvement or deterioration inacceleration properties was evaluated on the basis of the accelerationtimes for the commercial PG and the commercial RG. In the table, “Goodacceleration relative to the standard base fuel” was expressed as “O”(pass), “Same acceleration relative to the standard base fuel” wasexpressed as “Same”, and “Poor acceleration relative to the standardbase fuel” was expressed as “X” (fail)

TABLE 1 LLCO RON 95.0 Density g/cm³ 0.8626 Distillation IBP ° C. 166.5T10 ° C. 178.0 T30 ° C. 183.5 T50 ° C. 189.0 T70 ° C. 195.0 T90 ° C.202.5 EP ° C. 225.0 Composition C9+ aromatics Vol % 82.3 Indanes IndaneVol % 1.0 (2,3-dihydroindene) Methylindane Vol % 5.3 Dimethylindane Vol% 10.3 Trimethylindane Vol % 4.2 Total Vol % 20.8 Total calorific valueJ/cm³ 39100

TABLE 2 Emb. 1 Emb. 2 Comp.Ex. 1 Comp. Ex. 2 PG Vol % 93 96 85 100 LLCOVol % 7 4 15 RON 99.3 99.4 98.9 99.6 Density g/cm³ 0.7597 0.7578 0.77080.7494 Distillation IBP ° C. 29.5 29.5 30.5 30.0 T10 ° C. 48.5 46.5 50.545.5 T30 ° C. 71.5 70.0 77.5 67.5 T50 ° C. 100.5 97.5 108.0 94.0 T70 °C. 122.0 117.5 136.0 113.5 T90 ° C. 168.0 163.0 184.5 155.0 EP ° C.196.5 189.5 218.5 175.0 Composition CP+ aromatics Vol % 20.1 18.1 25.415.4 Indanes Indane (2,3-dihydroindene) Vol % 0.3 0.2 0.3 0.2Methylindane Vol % 0.4 0.2 0.8 0.0 Dimethylindane Vol % 0.7 0.4 1.5 0.0Trimethylindane Vol % 0.3 0.2 0.6 0.0 Total Vol % 1.7 1.0 3.2 0.2 Totalcalorific value J/cm³ 35580 35520 36000 35200 Fuel consumption % 1.3 1.1— Base Acceleration properties ◯ ◯ — Base

TABLE 3 Comp. Emb. 3 Emb. 4 Ex. 3 RG Vol % 93 96 100 LLCO Vol % 7 4 RON90.4 90.1 90.0 Density g/cm³ 0.7466 0.7422 0.7357 Distillation IBP ° C.34.5 33.0 33.0 T10 ° C. 52.5 51.0 50.5 T30 ° C. 72.5 71.0 68.5 T50 ° C.103.0 98.5 94.5 T70 ° C. 138.0 132.5 126.0 T90 ° C. 180.0 175.5 167.0 EP° C. 215.5 213.0 213.5 Composition CP+ aromatics Vol % 16.7 14.6 11.8Indanes Indane Vol % 0.3 0.2 0.2 (2,3-dihydroindene) Methylindane Vol %0.8 0.7 0.5 Dimethylindane Vol % 1.2 0.9 0.5 Trimethylindane Vol % 0.40.3 0.1 Total Vol % 2.7 2.1 1.3 Total calorific J/cm³ 35100 34960 34690value Fuel consumption % 1.3 1.2 Base Acceleration ◯ ◯ Base properties

As shown in Table 1, it was found that LLCO has a high research octanenumber. Thus, it is possible to use it as a blending component forgasoline-engine fuel compositions with good acceleration propertiesduring high-speed driving. It was also found that the per-volumecalorific value is high compared with commercial gasoline fuels. Thus,it is possible to use it as a blending component for gasoline-enginefuel compositions with good fuel consumption.

Also, for the compounded fuel composition for use in gasoline engines tosatisfy the JIS standard for gasoline (JIS K 2202), it is necessary toregulate the blend proportions so that T90 is not more than 180° C. andthe EP is not more than 220° C., but, as Table 2 shows, in ComparativeExample 1, which includes 15% by volume of LLCO, the distillationtemperature at 90 vol % distilled (T90) was found to exceed the 180° C.which is the JIS K 2202 standard. On the other hand, when the proportionof LLCO in the blend was not more than 10% by volume in the case of thePG, or not more than 7% by volume in the case of the RG, there was noimpact on practical performance, and it was thus found that it waspossible to compound a fuel composition for use in gasoline engines thatsatisfied the JIS standard.

Furthermore, in the case of Embodiment 1 to 3, in which the content ofaromatic hydrocarbons with 9 or more carbon atoms and the content ofindanes were higher than in the commercial gasolines (ComparativeExamples 2 and 3), it was shown that the acceleration properties at highspeeds (70 to 100 km/h) and the fuel consumption were improved.

1. A method for the preparation of a fuel compositions for use ingasoline engines, comprising subjecting the light cycle oil obtainedfrom a fluid catalytic apparatus to fractionation to produce a blendingcomponent and blending said blending component into a fuel composition.2. The method of claim 1 wherein the distillation characteristic of theblending component obtained by fractionation is from 160 to 230° C., thecontent of aromatic hydrocarbons with 9 or more carbon atoms is ofamount not less than 80% by volume and the indane content is of amountnot less than 20% by volume.
 3. The method of claim 1, wherein theamount of said blending component is in the range of from 4 to 10% byvolume.
 4. A blending component for automotive engine fuels, produced byfractionation of light cycle oil obtained from a fluid catalyticcracking apparatus and in that the distillation characteristic is from160 to 230° C., the content of aromatic hydrocarbons with 9 or morecarbon atoms is of amount not less than 80% by volume and the indanecontent is of amount not less than 20% by volume.
 5. The method of claim2 wherein the amount of said blending component is in the range of from4 to 10% by volume.